<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>06_外间距测试</title>
    <style>
        body {
            margin: 0;
        }
        * {
            margin: 0;
            padding: 0;
        }
    </style>
</head>
<body>
<div class="f">
  <div class="z1">1</div>
  <div class="z2">2</div>
  <div class="z3">3</div>
  <div class="z4">4</div>
</div>

</body>
</html>